deactivate range proof when it is an ownership transfer

token/core/zkatdlog/crypto/transfer/transfer.go

@@ -48,16 +48,19 @@ func NewProver(inputwitness, outputwitness []*token.TokenDataWitness, inputs, ou
 	for i := 0; i < len(outputwitness); i++ {
 		outW[i] = outputwitness[i].Clone()
 	}
-
-	p.RangeCorrectness = rangeproof.NewProver(outW, outputs, pp.RangeProofParams.SignedValues, pp.RangeProofParams.Exponent, pp.ZKATPedParams, pp.RangeProofParams.SignPK, pp.P, pp.RangeProofParams.Q, math.Curves[pp.Curve])
+	if len(inputwitness) != 1 || len(outputwitness) != 1 {
+		p.RangeCorrectness = rangeproof.NewProver(outW, outputs, pp.RangeProofParams.SignedValues, pp.RangeProofParams.Exponent, pp.ZKATPedParams, pp.RangeProofParams.SignPK, pp.P, pp.RangeProofParams.Q, math.Curves[pp.Curve])
+	}
 	wfw := NewWellFormednessWitness(inW, outW)
 	p.WellFormedness = NewWellFormednessProver(wfw, pp.ZKATPedParams, inputs, outputs, math.Curves[pp.Curve])
 	return p
 }
 
 func NewVerifier(inputs, outputs []*math.G1, pp *crypto.PublicParams) *Verifier {
 	v := &Verifier{}
-	v.RangeCorrectness = rangeproof.NewVerifier(outputs, uint64(len(pp.RangeProofParams.SignedValues)), pp.RangeProofParams.Exponent, pp.ZKATPedParams, pp.RangeProofParams.SignPK, pp.P, pp.RangeProofParams.Q, math.Curves[pp.Curve])
+	if len(inputs) != 1 || len(outputs) != 1 {
+		v.RangeCorrectness = rangeproof.NewVerifier(outputs, uint64(len(pp.RangeProofParams.SignedValues)), pp.RangeProofParams.Exponent, pp.ZKATPedParams, pp.RangeProofParams.SignPK, pp.P, pp.RangeProofParams.Q, math.Curves[pp.Curve])
+	}
 	v.WellFormedness = NewWellFormednessVerifier(pp.ZKATPedParams, inputs, outputs, math.Curves[pp.Curve])
 
 	return v
@@ -80,7 +83,9 @@ func (p *Prover) Prove() ([]byte, error) {
 
 	go func() {
 		defer wg.Done()
-		rangeProof, rangeErr = p.RangeCorrectness.Prove()
+		if p.RangeCorrectness != nil {
+			rangeProof, rangeErr = p.RangeCorrectness.Prove()
+		}
 	}()
 
 	wfProof, wfErr = p.WellFormedness.Prove()
@@ -121,7 +126,9 @@ func (v *Verifier) Verify(proof []byte) error {
 	go func() {
 		defer wg.Done()
 		// verify range proof
-		rangeErr = v.RangeCorrectness.Verify(tp.RangeCorrectness)
+		if v.RangeCorrectness != nil {
+			rangeErr = v.RangeCorrectness.Verify(tp.RangeCorrectness)
+		}
 	}()
 
 	wg.Wait()

token/core/zkatdlog/crypto/transfer/transfer_test.go

@@ -20,7 +20,7 @@ import (
 func TestParallelProveVerify(t *testing.T) {
 	parallelism := 1000
 
-	prover, verifier := prepareZKTransfer()
+	prover, verifier := prepareOwnershipTransfer()
 
 	var wg sync.WaitGroup
 	wg.Add(parallelism)
@@ -238,3 +238,55 @@ func prepareInvalidInputsForZKTransfer(pp *crypto.PublicParams) (*transfer.WellF
 
 	return transfer.NewWellFormednessWitness(intw, outtw), in, out
 }
+
+func prepareInputsForOwnershipTransfer(pp *crypto.PublicParams) (*transfer.WellFormednessWitness, []*math.G1, []*math.G1) {
+	c := math.Curves[pp.Curve]
+	rand, err := c.Rand()
+	Expect(err).NotTo(HaveOccurred())
+
+	inBF := c.NewRandomZr(rand)
+	outBF := c.NewRandomZr(rand)
+	ttype := "ABC"
+	inValue := c.NewZrFromInt(90)
+	outValue := c.NewZrFromInt(90)
+
+	in, out := prepareInputsOutputs([]*math.Zr{inValue}, []*math.Zr{outValue}, []*math.Zr{inBF}, []*math.Zr{outBF}, ttype, pp.ZKATPedParams, c)
+	intw := make([]*token.TokenDataWitness, 1)
+	for i := 0; i < len(intw); i++ {
+		intw[i] = &token.TokenDataWitness{BlindingFactor: inBF, Value: inValue, Type: ttype}
+	}
+
+	outtw := make([]*token.TokenDataWitness, 1)
+	for i := 0; i < len(outtw); i++ {
+		outtw[i] = &token.TokenDataWitness{BlindingFactor: outBF, Value: outValue, Type: ttype}
+	}
+	return transfer.NewWellFormednessWitness(intw, outtw), in, out
+}
+
+func prepareOwnershipTransfer() (*transfer.Prover, *transfer.Verifier) {
+	pp, err := crypto.Setup(100, 2, nil)
+	Expect(err).NotTo(HaveOccurred())
+
+	wfw, in, out := prepareInputsForOwnershipTransfer(pp)
+
+	inBF := wfw.GetInBlindingFators()
+	outBF := wfw.GetOutBlindingFators()
+
+	inValues := wfw.GetInValues()
+	outValues := wfw.GetOutValues()
+
+	ttype := "ABC"
+	intw := make([]*token.TokenDataWitness, len(inValues))
+	for i := 0; i < len(intw); i++ {
+		intw[i] = &token.TokenDataWitness{BlindingFactor: inBF[i], Value: inValues[i], Type: ttype}
+	}
+
+	outtw := make([]*token.TokenDataWitness, len(outValues))
+	for i := 0; i < len(outtw); i++ {
+		outtw[i] = &token.TokenDataWitness{BlindingFactor: outBF[i], Value: outValues[i], Type: ttype}
+	}
+	prover := transfer.NewProver(intw, outtw, in, out, pp)
+	verifier := transfer.NewVerifier(in, out, pp)
+
+	return prover, verifier
+}